Why does logical absence vs opponents barely happen?

Joel was out today with the same sprained foot that he seemingly had all week and had him as a game-time decision in Brooklyn, to which he then played. Brooklyn literally had no one and were never a chance to beat even a Joel-less Sixers. How hard is it to think ahead: 'If the foot is vulnerable, let's sit Joel for Brooklyn and he can play vs Phoenix'. I know it's not always as simple as that but over the years it's like they never think of these things ffs.

Also I've barely got any "adjustment period" patience left for PG. If the jumpshot ain't falling go to the fucking cup man.